   "Calculates the relative y-positions of blocks within a class. If the class
   was compacted upward, we start at the top and walk down the class; for
   downward, at the bottom, walking up."
-  [class block-edges node-sep char-sep compacted]
+  [class block-edges node-sep char-sep compaction]
   (let [filter-set (set class)
-        rel-op ({:up + :down -} compacted)]
+        rel-op ({:up + :down -} compaction)]
     (reduce (fn [ys block]
               (let [in-class-edges (filter #(contains? filter-set (:dest %))
                                            (get block-edges block))

                 [{} #{}]
                 start-blocks)))


(defn block-info->ClassGraph
  "For a particular blockification, compacts these blocks in to a ClassGraph,
  in either an :up or :down direction"
  [block-info compacted]
  (let [block-keys (if (= compacted :up)
                     [:blocks-up :simple-succs :sources]
                     [:blocks-down :simple-preds :sinks])
        [blocks classify-edges start-blocks] (map block-info block-keys)

                classes-set)
        sources (set/difference classes-set (set (keys preds)))
        sinks (set/difference classes-set (set (keys succs)))
        classes (if (= compaction :up)
                  (let [simple-succs (->> succs
                                          (map (fn [[src edges]]
                                                 [src (set (map #(get-in
